A battery module for an electric vehicle or a hybrid vehicle includes a plurality of cells that are arranged next to each other. Each of the cells includes a flat body having a power generation element therein and positive electrode and negative electrodes. The electrodes of adjacent cells are connected via a connecting member to connect the cells in series or in parallel.
Patent Document 1 below describes a battery wiring module that includes a connecting member, a voltage sensing wire configured to determine the voltage of the cell, and a base that houses the connecting member and the voltage sensing wire. The battery wiring module is attached to a cell group such that an electrode terminal of each cell is passed through a terminal through hole formed in each connecting member. Then, a nut is screwed and fastened to electrically connect the cells. The base includes a pair of locking protrusions that prevents the connecting member from slipping out of the base. When the connecting member is inserted into the base, the locking protrusions are elastically deformed to allow the connecting member to be inserted into the base. After the insertion, the locking protrusions are elastically restored to lock the connecting member.